Micro-electromechanical systems (MEMS) may comprise movable micro-mirrors fabricated by microelectronic processing techniques on wafer substrates. Electrostatic actuation is most commonly used to deflect micro-mirrors. In order to produce a force, a voltage is generated between two electrodes, one of which is stationary and the other of which is attached to an actuator for example the movable micro-mirror.
An SLM with an array of actuators used in for example a mask writing tool or a chip manufacturing tool is loaded with a specific pattern, where each actuator is in an addressed state or a non-addressed state before each stamp is printed. This pattern may be a subset of the pattern to be printed on the mask or chip respectively. Each actuator mirror is deflected electrostatically by applying voltage between the mirror and an underlying address electrode, after which the actuator mirror is allowed to move into its predetermined deflected state before an electromagnetic radiation source is triggered to print the stamp.
A deflection amplitude of the actuator mirror in a spatial light modulator (SLM) is determined by a number of factors such an addressing voltage, mirror hinge material stiffness, mirror hinge thickness, electrode to mirror distance etc. With otherwise optimized parameters the addressing voltage is usually the determining free parameter for being able to reach the maximum required mirror deflection amplitude. This, in turn, sets the requirements for a voltage span of an addressing CMOS circuit. As a mirror area needs to shrink for future generations of SLM components to allow more mirrors per SLM chip, the addressing voltage will need to increase dramatically for otherwise unchanged parameters. A size of a pixel cell in the CMOS circuit is strongly dependent on the voltage span of the addressing CMOS circuit, why for smaller mirror sizes, with increased addressing voltage span, the CMOS circuit becomes the limiting factor for future actuator sizes.